Drum mixer for mixing wood wool with a binder



United States Patent Inventor Appl. No. Filed Patented DRUM MIXER FOR MIXING WOOD WOOL WITI-I Primary Examiner-William I. Price Attorney-James P. Welch ABSTRACT: In a drum mixer for mixing wood wool with a binder such as cement, rods are arranged at the smooth inside wall of the horizontal drum in two longitudinal rows diametrically opposed to each other. These rods have a large interififif Drawin m 8 space and mix the inserted wood wool with the binder. g g Because of the large distance of said rods the wood wool fibres U.S.Cl i 259/3 cannot felt and by rolling and sliding movements automati- Int. Cl B01f9/02 cally clean the inside drum wall. The drum also stores the Field olSearch 259/3, 30, wood wool and thereby allows a permanent operation of the 81; 118/418; 68/144; 69/30 machines producing the wood wool.

l" f 3 ii. i t i. 6 i1, \i l 1 F e, 's'\ T I 4 77 2 A a I Patented Dec. 1, 1970 DRUM MIXER FOR MIXING WOOD WOOL WITH A BINDER The invention relates to a drum mixer for mixing wood wool with a binder such as cement. This drum mixer consists of a drum which rotates around a horizontal axis, to the inside of which internally directed radial rods are secured. The drum has a minimum diameter of2 meters and a length ofa multiple thereof. At the front wall, the drum is provided with a feeding opening and at the end wall with an outlet opening.

In a prior art structure of the drum mixer for wood wool, short rods are bent in the shape of hooks in the direction of rotation of the drum and are fastened to parallel longitudinal bars forming a cylindrical cage. Because of the small space between the single rows of these rods the binding agent may deposit itself on them and the wood wool fibres may easily felt in the hook shaped ends of the rods. Such mixer is therefore not suitable for mixing long fibre wood wools with a binder. Also, because of its great susceptibility to interference, it does not assure reliable continuous service.

An important object of this invention is to provide a drum mixer for mixing wood wool with a binder by which the above described disadvantages are avoided.

Another object is the provision of a drum mixer which sparingly deals with the wood wool when it is mixed with the binder.

A further object of the invention is to provide a drum in which depositing of the mixture inside the drum is eliminated.

A specific object of this invention is to provide a drum mixer by which the issuance of the mixture can be conveniently adjusted to individual service requirements.

These and other objects of this invention will become apparent from the following description in combination with the accompanying drawings, in which several embodiments of the invention are shown by way ofexample:

FIG. 1 is a lateral view of a drum mixer with a horizontal drum mounted on rollers;

FIG. 2 is a sectional view taken along the line Il-II of FIG. 1;

FIG. 3 is a partial side view of one of the parts provided with apertures for the issue of the mixture;

FIG. 4 is a lateral view of a drum mixer for automatic operation.

In the drum mixer of the described type an essential feature of the invention comprises the arrangement of the rods at the inside wall of the horizontal drum in a large distance from one another. For instance, if the length of the drum is 8 meters, there are provided approximately eight rods, hence, one rod on 1 meter length of the drum. The rods have a length of approximately one third to one fourth of the diameter of the drum. In a preferred embodiment of this invention the rods are arranged in a few longitudinal rows diametrically opposed to each other, and the rods are inclined against the vertical line in the direction of the outlet opening. The outlet aperture preferably consists of a plurality of openings, which are arranged on the circumference of the drum at its end portion and are of adjustable sizes.

Compared to the conventional constructions of drum mixers the arrangement of the radial, internally directed rods according to the invention with a big space between the single rods, in combination with the inclination of the rods towards the outlet opening, enables a sparing treatment of the long wood wool fibres during the mixing process because the fibres are pulled apart by the spaced rods in the course of the slow rotation of the large drum and therefor cannot felt with one another. During the mixing process, the wood wool slides along the slowly rotating inside wall of the drum and in the course of this carries out a simultaneous rolling and sliding movement which causes it to be homogeneously mixed with the binder. Apart therefrom, the inside wall of the drum is kept clean and is protected from deposits, which ensures an uninterrupted state of operativeness without it being necessary in the meantime to halt its operation and clean the inside of the drum and the rods. As the drum apertures for issuance of the mixture are provided opposite to its feeding end, only the external fibres of the wood wool mixture falling onto the respective issue aperture are taken away to the outside. The wood wool fibres are therefor in even layers deposited on the conveyor belt which is in a conventional manner mounted beneath the issue aperture. This results in a favourable influence on the wood wool boards manufactured from the wood wool mixture.

Due to its large size, the drum at the same time takes the function ofa reservoir, absorbing fluctuations of the production and supply of wood wool by the planning machines or interruptions of succeeding working stages. The adjustability of the size of opening of the issue apertures to a large extent makes it possible to adapt the machines arranged behind the drum in line with the performance of the wood wool planning machines which during interruptions of the operation of said machines can work further as also larger quantities of the produced wood wool are stored in the drum.

As another feature of the invention, sliders are arranged above the issue apertures of the drum which are to adjust the size of issue opening. These sliders preferably are coupled with a controlling apparatus which is coaxial with the drum and movable relatively of it. For adjustment of the quantity of mixture release, it is preferable to connect the sliders with a cylinder which is actuated by fluid means. When the mixer is automatically operated the cylinder may be controlled by impulses regulating the opening section of the issue apertures in dependence of the degree of filling of the drum. Alternatively, the sliders may be actuated by a regulating device in dependence of weight or volume of the mixture. This regulating device may be coupled to a feeler provided at the conveyor belt underneath the issue aperture and operating to decrease the section of the opening if the conveyor belt takes too large quantities of the mixture. By this regulating device the quantity issued from the drum may be maintained at a certain level. The sliders can be wholly closed independent of the regulating device when a distributor equipment arranged behind the drum mixer is stopped, e.g. when the thickness of the produced building plates is changed.

Referring now particularly to FIGS. 1 and 2 of the drawings, a drum 1 rotating around a horizontal axis, is at one end provided with a feeding opening 3 and is at the same end mounted on rollers 2. At its opposite face the drum 1 is coupled with a coaxial shaft 13 which is operated by a chain transmission 4 and a motor 5. Alternatively, the drum may be driven by the rollers 2, which would in this case be provided with rubber layers. The horizontal shaft 13 is supported by a bearing 6.

The drum 1 is ofa length of, for instance, 8 meters. Secured to its inside wall are eight radially directed rods 7, each of a length of one third to one fourth of the diameter of drum 1, and being inclined towards a vertical plane in the direction of the issue apertures 8. The rods 7 are arranged in two rows which are disposed diametrically to one another.

The issue apertures 8 consist of a plurality of openings applied to the circumference of drum 1 at the opposite end of the feeding opening 3. Above each opening 8 a slider 9 is provided by which the section of openings 8 can be varied according to working requirements. A conveyor belt 10 is arranged beneath openings 8 to convey the wood wool mixture released from the drum to a plant for manufacture of wood wool plates, either directly or via a weight or volume dependent proportioning plant. By a feeding device 11, such as a conveyor belt with lateral ledges, chemically moistened wood wool 12 and cement, which serves as a binding agent, and, if required, colour additions, are inserted into the feeding opening 3 of drum 1. Instead of moistened wood wool the drum can be charged with proportioned dry wood wool and separated liquid.

After drum 1 has been filled with the wood wool 12 and the binder it is slowly rotated. In the course of rotation, the wood wool mixture rolls off and partly slides downwards in the area of the lower upwardly moving drum wall, in a manner indicated by arrow 14 of FIG. 2. This rolling motion is interrupted by the upwardly moving rods 7, and the quantity of wood wool mixture picked up by them and taken along upwards in free fall, as indicated by arrow gets back from the area of the upper dead center of the rods 7 into the lower area of the drum, which causes the wood wool to form a homogeneous mixture with the cement. By its sliding, the wood wool has a cleaning effect on the inside wall of the drum, thus keeping it clear and rendering unnecessary any particular cleaning measures, neither during nor after operation. The wood wool fibres are neither broken nor damaged because the fibres picked up by the rods 7 are slowly pulled out of the rolling and sliding mass and therefore the single fibres have sufficient time to separate from one another.

For quick adjustment of the effective opening size of the issue apertures 8, the sliders 9 are mounted at a disk 16, as shown in FIG. 3, the shaft 17 of which turns in a bearing 18, in which it can also be axially shifted, and is via a claw coupling 19 linked with a lever 20 which has a catch device 21. By lowering lever 20 into a lower catch position the section of the issue opening 8 is increased. in this construction, drum 1 may alternatively be mounted and rotated on rollers 22 at. its issue end.

In the embodiment of FIG. 4, the axial guidance ofdrum l is provided by vertically mounted rollers 23, in gear with which are shrouding rings 24 connecting the singledrum sections with each other. The disk 16, which carries the sliders 9, is by two cams 25 connected with drum 1. Instead of by the lever 20, the sliders 9 are rapidly closed and opened by a pneumatically operated cylinder 27, the piston of which gears via a coupling 26 with the axially adjustable shaft 17. The cylinder 27 may be under remote control, for instance by impulses of the switch gear of the distributor equipment arranged behind the drum mixer.

For adjusting the discharge mixture a hydraulic control cylinder 31, a spindle drive or any other rigid adjusting device are provided behind the pneumatic cylinder 27. Alternatively, the remote control of cylinder 31 may be effectuated by means of a feeler roll 28 shown in FIG. 2, which is mounted above the conveyor belt 10, and an interposed regulation device 29, in such a manner that the sliders 9 diminish the section of the issue openings 8 when drum 1 releases too big quantities of mixture.

As shown in FIG. 4 the regulation device 29 may be connected to the hydraulic cylinder 31 which is coaxial with the axially displaceable shaft 17, and the piston rod of which, facing the pneumatic cylinder 27, is at its end provided with a shoulder 30. In this construction the pneumatic cylinder 27 is double acting in order to effectuate rapid closing of the openings 8 by the sliders 9, the respective positions of which, governing the respective opening sections of the apertures 8, are determined by the unchanged shoulder of hydraulic cylinder 31. The sliders 9 can be controlled instead by a discharge quantity of drum 1 dependent from the degree of filling of drum 1 which is measured e.g. by the current consumption of driving motor 5.

The regulation device 29 in connection with the current consumption of driving motor 5 and the hydraulic cylinder 31, which operates as a rigid adjusting element, allows a wide scope of adjustment of the quantity of mixture to be released from and/or of the degree of filling of drum 1. In case of need, for instance when the succeeding plant for manufacture of the wood wool boards becomes inoperative on account of interference or for changing the size of the plates, etc., the issue openings 8 of drum 1 can quickly be closed by the pneumatic cylinder 27 without it being necessary to lay idle the single processing machines of the plant, such as wood wool planning machines, weighing and moistening machines, or to cause the workmen to withdraw the wood from the planning machines, as the wood wool manufactured during the standstill of the distributor plant may be stored within drum 1, which allows a marked increase in the daily performance of the plant and enables an uninterrupted continuous operation of the planning machines.

This storage capacity renders superfluous the otherwise necessary switchoff couplings of the planning machines, which allows a maximum performance of these machines. Excessive wood wool quantities may be stored to balance short supply of it at a later time on account of thinner woods processed.

The only few rows of distantly spaced rods of the drum continually loosen up the moist wood wool and cement mixture without allowing any formation of felted bales. Since the wood wool mixture is kept in the slowly rotating drum for some length of time the water portion of the mixture may fully penetrate into the cells of the wood wool fibres. The mixture therefor leaves the drum outwardly drier than it has been the case so far, which causes the wood wool plates to receive a particularly high degree of firmness due to the fact that the water contained in the wood wool fibres is during the binding process slowly returned into the cement. The outwardly drier mixture provides a further advantage in that the distributor plant and the moulds for production of the wood wool plates are not contaminated to the same extent. Besides, the wood wool plates may be pressed on more heavily without pressing the water out of them. The particles of the mixture, such as the wood wool, cement, and, if applied, colour additions, are mixed to a high degree so that the wood wool plates receive a very even structure.

The drum mixer according to the invention may be operated continually for 24 hours daily as the drum need not be cleaned. This saves a lot of cement and working time. Because of the regulation of its release quantities the plant is of a considerably higher performance than the ones known up to now and enables manufacture of high quality plates as the mixer does not drop cement lumps and the wood wool fibres are sparingly treated.

Having thus described my invention, I wish to add that the embodiments shown in the drawing and described in the specification shall be understood to be mere examples and therefor other modifications or alterations of parts as may be suitable in different circumstances are understood to be fully within the scope of the specification and appended claims.

I claim:

1. A drum mixer for mixing wood wool with a binder, com prising a drum rotating around a horizontal axis, said drum having a minimum diameter of two meters, a length of a multiple thereof, and a smooth inside wall, a feeding opening at one end and an issue aperture at the opposite end of said drum, radial internally directed rods fastened to the inside wall of said drum, said rods are spaced from one another at a large distance.

2. A drurn mixer according to claim 1, wherein on each meter of the length of said drum one rod is provided, the length of said rods is approximately one third to one fourth of the diameter ofthe drum.

3. A drum mixer according to claim 1, wherein the rods are arranged in only two longitudinal rows diametrically opposed to each other.

4. A drum mixer according to claim 1, wherein the rods are inclined against the vertical plane in the direction of the issue aperture of said drum.

5. A drum mixer according to claim 1, wherein the issue aperture of said drum consists of a plurality of openings adjustable in size and provided at the end of said drum on its circumference.

6. A drum mixer according to claim 5, wherein the section of the issue aperture of said drum is adjustable by sliders coupled with a regulating device arranged coaxially with and movable relatively to said drum.

7. A drum mixer according to claim 6, wherein the sliders are for adjustment of the issue quantity of mixture coupled with a cylinder operable by pressure media.

8. A drum mixer according to claim 7, wherein the sliders are adjustable in dependence of the degree of filling of the drum.

9. A drum mixer according to claim 7, wherein the sliders are adjustable in dependence of the capacity of a succeeding processing machine for the mixture.

10. A drum mixer according to claim 8, wherein the sliders 11. A drum mixer according to claim 6, wherein the sliders are by a regulating device in connection with a rigid adjusting are coupled with a double-acting air cylinder which effectuelement automatically adjustable in dependence of the quantiates a rapid closure of the sliders without change of the irty of mixture issued from the drum. respective adjustment. 

